Face bit



July-30, 1935- Y w. J. MITCHELL 2,009,742

mom BIT Filed May 15, 1933 gwuemm Patented July 30, 1935 I UNITED STATES PATENT OFFICE FACE BIT William J. Mitchell, San Francisco, Calif., as-

signor to Chicago Pneumatic Tool Company, New York, N. Y., a corporation of New Jersey Application May 15, 1933, Serial No. 611,265 3 Claims. (01. 255-61) My present invention relates to a novel face staggered arrangement of the water-distributing bit of the rotary, diamond type especially for the holes, and showing, for convenience of illustrause with machines engaged in boring or drilling tion only a sector or segment of the cutting face grout holes for dam sites,.boring blasting holes, set with diamond cutters, and Figure 4 is a simi- 5 mining, exploration work, and other similar earth lar view showing the radially extending, curved 5 boring or drilling operations. The face bit is conveyor grooves for the dbris. Figure 5 is 9. adapted for use at the lower end of the tubular side view of the bit of Figure 4. Figure 6 shows drill rod of the drilling machine, and this drill one of the bits equipped with a cylindrical coubit is readily interchangeable with a core-bit that pling having reaming cutters.

10 may be substituted for the face bit when an in- The'face bit of my invention is attached at the 10 spection-sample of the earth is desired during the lower end of the lowest tubular section of the boring of a, hole. usual tubular drill rod-as I, and the bit 2 is fash- The face-bit is supplied with water to assist ioned with an exteriorly threaded shank 3 which in the cutting operations, and means are prois threaded into the complementary interior vided for passing the water from the interior of threads of the tubular section of the drill rod. 5 the toolto the exterior or working face of the bit As shown, the bit is hollow and has an exterior where it is uniformly distributed in the cutting diameter slightly less than the' bore of the drill or boring area without materially reducing the rod in order that the water may fl W downwa darea of the diamond cutters,'and means are pro- 3' through e ubular rod to the rounded intevided for conveying the debris or cuttings of the, ri r chamber of the bit. 20 tool to the annular space between the rotary tool" e cutting face 4 0f the bit is tapered, and the wall of the bored hole in order that the ro d, circu ar or p e ab y, as s ow he dbris may be lifted by the water to the surface p i and merges with the exterior Cylindriof the drilled gro nd, cal periphery of the bit proper. The cutting face By'the utilization of the bit of my invention I is p vi ed wi t usual diamond cutters 5 that 25 v h i a t al ra ti h d th speed of are set in proper manner in the metal of the face, boring operations, materially reduced the expense for the Cutting drilling Operation, d n adand time of operating a drilling machine, i dition to these cutters 5, an annular series of creasedthe durability of the usual bits, and proreaming cutters 5 is Set in the Cylindrical Po t n vided a reliable and strong drilling bit that may of the bit for the D -D of enlarging the hole 30 40 practical'application of the principles of my inbe rotated at greater speed than the speed of as it s o d. The enlarged hole, as w be 1mth ordinary bit w i derstood, provides an annular space around the My i ti i t i certain n0ve1 exterior of the drill rod for the upward flow of binations and arrangements of parts as will herewater and debris from the cutting face of the bit.

inafter be more fully set forth and claimed. In water flowing t ollgh t e interior of 35 the accompanying drawing I have illustrated the drill lOd reaches the interior Of the hOllOW several examples of the novel features of my in n is passed o the erior of the face vent-ion wherein the parts are combined and arthrough holes as 1, d which, a ndicated ranged according to modes so far devised for the in Figures 3 and 4 are Staggered, t paced at unequal distances from the center of the bit, 40 vention. While the illustrated tool is successin order that the metal face may not be material fully operating in actual practice, it will be un- 1y weakened, and in orderv that the cutters 5 may derstood that the exemplified structures may be be Set to the face of the bit to accomplish a a altered or changed, withi th scope of my mum result in the cutter operation. The holesclaims, without departing from the principles of are s staggered that one of these u in 45 my invention. portions of the face will not follow another non- Figure 1 is a side view at the lower or bit end cutting portion as the bit s, d t s stasof a rotary tubular drilling tool equipped with the gered arrangement of the holes distributes the face bit of my invention. water over an area of the face from near the cen- Figure 2 is an enlarged view similar to Figure l 0 t e t to pp a e y t at portion of 50 l, but showing the face bit equipped with a special the cutting face having the maximum diameter. tapered reaming device, and also showing the By the means, the water passing through the face bit partly broken away for convenience of holes I, 8, and 9, is uniformly distributed over illustration. the entire cutting face of the bit to facilitate the Figure 3 is a face view of the bit, showing the cutting operation, as the bit rotates or revolves. 56

These holes I, 8, and 9,in the wall of the bit, are enlarged as at 9' where they open into the interior chamber of the head of the bit in order to prevent clogging of the holes by the dbris. Thus, should the dbris be forced into the holes against the down fiow of the water in the tool, the enlarged inner portions of the holes permits the dbris to spread and the flow of water insures a loose condition in the dbris that eliminates clogging or packing of the holes.

In order to convey the cuttings or dbris away from the cutting face of the bit, and thus prevent clogging and inefficient work of the bit, I provide a series of grooves l0, here shown as three in number, but it will be understood that the number of grooves may be varied. These grooves I0 are fashioned in the cutting face and extend from the center of the face of the bit to the annular periphery of the bit, starting at the center with I a zero depth and increasing in depth and width to their outer ends where the maximum depth and width is attained. Preferably the grooves extend radially from the center, with a curved formation, so that the trailing edges of the groove, as the bit rotates, tends to pass or convey the dbris from the center toward the periphery of the bit face. The water flowing through the holes I, 8, and 9, assists in conveying the dbris or cuttings to the periphery of the bit face, and then the upwardly moving column of water in the annular space about the exterior of the drill rod lifts this dbris to the ground surface.

In Figure 2 I have shown the face bit in use with a coupling section II that is attached at the lower end of the drill rod section I, and the hollow face bit is threaded in the lower end of this coupling. At its lower end the coupling is fashioned with an annular, tapered or beveled face I2 having its smaller diameter complementary to the outer diameter of the bit, and its larger diameter complementary to the larger exterior periphery of the drill tool section I. In this conical, tapered or beveled face I2 are set the diamond cutters l3, which, in addition to the annular series of reamers 6 of the bit, serve as reaming cuttersfor enlarging the bored hole. These reaming cutters as shown are set up above, or spaced above, the cutters on the bit, and they are especially advantageous in some boring or drilling operations where reaming of the bored hole is required.

In Figure 6 a cylindrical coupling I4 is illustrated, which may be employed in lieu of the tapered coupling II in Figure 2, and this coupling is provided with the reaming cutters I 3 some distance above the face of the bit to enlarge the hole.

As thus constructed and arranged the drill is capable of boring a straight hole through the earth regardless of the nature of the soil, with a speed not heretofore attainable with drill bits now in use. The presence of the water which flows down through the drill tube and carries the dbris up through the hole, eliminates the creation of dust that usually accompanys drilling and boring operations of this nature, and as this dust is unhealthy and unsanitary, it will be apparent that the attendants or operators working about the hole are protected from the deleterious effects of dust. The smooth and easy operation of the drilling tool permits the use of a compactly arranged electric motor for supplying the power to the machine, a use not attainable under ordinary conditions where a hammer type of drill is used.

During the boring operations, if it is desired to employ a core bit, to extract the sample of the earth through which the bit is passing, the drill rod may be withdrawn, the face bit removed, and a core bit substituted therefor, with convenience and without material loss of time. After a sample has been secured the tool may again be withdrawn, and the face bit substituted for the core bit.

In actual practice the face bit of my invention has proven highly satisfactory in materially reducing the cost of maintenance of the drilling machine; in enhancing the speed at which the rotary tool may be operated, and in reducing the time required for drilling a hole, regardless of the depth of the hole.

Having thus fully described my invention, what I claim as new and desire to secure by Letters Patent is:

1. A hollow, cylindrical, rotary, boring bit having a hemi-spherical cutting face and cutters set in said face, said bit having three water holes arranged on a spiral line about the center of the bit, said water holes having a maximum cross area at the inner side of the face of thebit and a minimum cross area at the outer side of the face of the bit, said bit having a groove in its face between each pair of adjoining water holes, and said grooves increasing in cross area from the center of the bit to the cylindrical periphery of the bit.

2. A hollow, cylindrical, rotary, boring bit having a hemi-spherical cutting face and cutters set in said face, and an annular series of reaming cutters extending laterally from the cylindrical periphery of the bit, said bit having three spirally arranged water holes in its face each having a maximum cross area at the inner side of the face of the bit and a minimum cross area at the outer side of the face of the bit, said bit also having a groove in its face between each pair of adjoining water holes, and said grooves increasing in cross area from the center of the bit and terminating approximately at the line of the reaming cutters.

3. A hollow, cylindrical, rotary, boring bit having a hemi-spherical cutting face and cutters set in said face, said bit having a plurality of water holes arranged on a spiral line about the center of the bit, said water holes having a maximum cross area at the inner side of the face of the bit, and a minimum cross area at the outer side of the face of the bit, said bit having a groove in its face between each pair of adjoining water lgqles, and said grooves increasing in cross area from the center of the bit to the cylindrical periphery of the bit.

WILLIAM J. MITCHELL. 

